Decelerator typically is classified into a constant speed decelerator outputting a driving force at a constant deceleration speed in combination with the gears each having different sizes, and a continuously variable transmission changing a deceleration ratio by adapting a conical decelerator.
The rotational force from a driving generation apparatus such as a motor or an engine is outputted at a high rotation speed, but with less torque. In most of industrial machines, a decelerator is typically used, thus augmenting torque.
Here, the decelerator is directed to decelerating the revolutions from a driving force generation apparatus while increasing torque.
The decelerator decreases the revolution from a driving force generation apparatus, but increases and outputs the torque. In this case, when the load applied to the output shaft is higher than the output torque of the output shaft, such load might be reversely applied to a motor or an engine, thus decreasing the life span of a motor or an engine.
The load higher than the output torque of the output shaft is applied to a motor or an engine in a reverse direction, which inhibits a desired output from being transferred to the output shaft.
The non-stage transmission is disclosed in Korean patent application with the application number of 2007-0064349 which is originally intended to overcome the above problems.
The conventional non-stage transmission comprises a lever crank mechanism between an input shaft rotating in one direction by means of an external force (motor or engine), and an output shaft receiving a driving force of the input shaft and transferring the driving force.
The lever crank mechanism is a known mechanism allowing an output shaft converting one direction rotational movement of the input shaft to reciprocate within a certain angular range. There is a wiper driven apparatus which uses the above known mechanism.
However, the conventional non-stage transmission using the lever crank mechanism is directed to adapting a way that a driving force transfer system is deviated in one side, the operation of which leads to less vibrations and noises.